The Chevrolet Performance LSX bare block is a finished-bore cast iron LS cylinder block engineered for large-displacement, high-horsepower and forced-induction LS builds. The 4.185 in bore arrives finished and ready for assembly, and the block adds extra head-bolt provisions for improved clamping under boost.
Specifications:
- LSX bare cylinder block
- Material: cast iron
- Bore: 4.185 in, finished
- Deck height: 9.240 in
- Main caps: standard location, 6-bolt
- Head bolt provision: 6-bolt per cylinder
- Rear seal: 1-piece
- Finish: orange
- Fits GM LS-Series architecture
- Part number: 19417353
Applications:
- GM LS-Series engine platform (LSX race block)
FAQ
Is the 4.185 in bore finished?
Yes, it is machined to a finished size and ready for ring fitment and assembly.
What is the head bolt arrangement?
The block provides six head bolts per cylinder for increased clamping load under high cylinder pressure.
What rear main seal does it use?
It uses a 1-piece rear main seal.
What engine family does this block fit?
It fits the GM LS-Series architecture as part of the LSX race block line.

